powerpc/64: use 32-bit immediate for STACK_FRAME_REGS_MARKER
Using a 32-bit constant for this marker allows it to be loaded with two ALU instructions, like 32-bit. This avoids a TOC entry and a TOC load that depends on the r2 value that has just been loaded from the PACA. This changes the value for 32-bit as well, so both have the same value in the low 4 bytes and 64-bit has 0 in the top bytes. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220926034057.2360083-2-npiggin@gmail.com
This commit is contained in:
Nicholas Piggin
Michael Ellerman
parent
4b2a9315f2
commit
17773afdcd
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@ -99,6 +99,8 @@ struct pt_regs
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#define STACK_FRAME_WITH_PT_REGS (STACK_FRAME_OVERHEAD + sizeof(struct pt_regs))
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#define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
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#ifdef __powerpc64__
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/*
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@ -115,7 +117,6 @@ struct pt_regs
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#define STACK_FRAME_OVERHEAD 112 /* size of minimum stack frame */
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#define STACK_FRAME_LR_SAVE 2 /* Location of LR in stack frame */
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#define STACK_FRAME_REGS_MARKER ASM_CONST(0x7265677368657265)
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#define STACK_INT_FRAME_SIZE (sizeof(struct pt_regs) + \
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STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
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#define STACK_FRAME_MARKER 12
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@ -136,7 +137,6 @@ struct pt_regs
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#define KERNEL_REDZONE_SIZE 0
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#define STACK_FRAME_OVERHEAD 16 /* size of minimum stack frame */
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#define STACK_FRAME_LR_SAVE 1 /* Location of LR in stack frame */
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#define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
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#define STACK_INT_FRAME_SIZE (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
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#define STACK_FRAME_MARKER 2
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#define STACK_FRAME_MIN_SIZE STACK_FRAME_OVERHEAD
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@ -263,7 +263,7 @@ fast_exception_return:
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mtcr r10
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lwz r10,_LINK(r11)
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mtlr r10
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/* Clear the exception_marker on the stack to avoid confusing stacktrace */
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/* Clear the exception marker on the stack to avoid confusing stacktrace */
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li r10, 0
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stw r10, 8(r11)
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REST_GPR(10, r11)
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@ -320,7 +320,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
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li r0,0
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/*
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* Leaving a stale exception_marker on the stack can confuse
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* Leaving a stale exception marker on the stack can confuse
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* the reliable stack unwinder later on. Clear it.
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*/
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stw r0,8(r1)
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@ -372,7 +372,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
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mtspr SPRN_XER,r5
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/*
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* Leaving a stale exception_marker on the stack can confuse
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* Leaving a stale exception marker on the stack can confuse
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* the reliable stack unwinder later on. Clear it.
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*/
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stw r0,8(r1)
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@ -378,7 +378,7 @@ exc_##n##_common: \
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ld r9,excf+EX_R1(r13); /* load orig r1 back from PACA */ \
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lwz r10,excf+EX_CR(r13); /* load orig CR back from PACA */ \
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lbz r11,PACAIRQSOFTMASK(r13); /* get current IRQ softe */ \
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ld r12,exception_marker@toc(r2); \
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LOAD_REG_IMMEDIATE(r12, STACK_FRAME_REGS_MARKER); \
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ZEROIZE_GPR(0); \
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std r3,GPR10(r1); /* save r10 to stackframe */ \
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std r4,GPR11(r1); /* save r11 to stackframe */ \
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@ -459,12 +459,6 @@ exc_##n##_bad_stack: \
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bl hdlr; \
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b interrupt_return
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/* This value is used to mark exception frames on the stack. */
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.section ".toc","aw"
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exception_marker:
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.tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
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/*
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* And here we have the exception vectors !
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*/
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@ -589,7 +589,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR)
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li r9,IVEC
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std r9,_TRAP(r1) /* set trap number */
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li r10,0
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ld r11,exception_marker@toc(r2)
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LOAD_REG_IMMEDIATE(r11, STACK_FRAME_REGS_MARKER)
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std r10,RESULT(r1) /* clear regs->result */
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std r11,STACK_FRAME_OVERHEAD-16(r1) /* mark the frame */
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.endm
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@ -192,13 +192,6 @@ __secondary_hold:
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#endif
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CLOSE_FIXED_SECTION(first_256B)
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/* This value is used to mark exception frames on the stack. */
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.section ".toc","aw"
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/* This value is used to mark exception frames on the stack. */
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exception_marker:
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.tc ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER
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.previous
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/*
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* On server, we include the exception vectors code here as it
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* relies on absolute addressing which is only possible within
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@ -80,7 +80,7 @@ _ASM_NOKPROBE_SYMBOL(system_call_vectored_\name)
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/* Calling convention has r3 = regs, r4 = orig r0 */
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addi r3,r1,STACK_FRAME_OVERHEAD
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mr r4,r0
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ld r11,exception_marker@toc(r2)
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LOAD_REG_IMMEDIATE(r11, STACK_FRAME_REGS_MARKER)
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std r11,-16(r3) /* "regshere" marker */
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BEGIN_FTR_SECTION
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@ -253,7 +253,7 @@ END_BTB_FLUSH_SECTION
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/* Calling convention has r3 = regs, r4 = orig r0 */
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addi r3,r1,STACK_FRAME_OVERHEAD
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mr r4,r0
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ld r11,exception_marker@toc(r2)
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LOAD_REG_IMMEDIATE(r11, STACK_FRAME_REGS_MARKER)
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std r11,-16(r3) /* "regshere" marker */
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#ifdef CONFIG_PPC_BOOK3S
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@ -614,7 +614,7 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
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mtspr SPRN_XER,r5
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/*
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* Leaving a stale exception_marker on the stack can confuse
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* Leaving a stale STACK_FRAME_REGS_MARKER on the stack can confuse
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* the reliable stack unwinder later on. Clear it.
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*/
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std r0,STACK_FRAME_OVERHEAD-16(r1)
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